1. Field of the Invention
The present invention relates to a capsule-type endoscope which is introduced into a test subject to observe a test region.
2. Description of the Related Art
In recent years, a capsule-type endoscope has been proposed in the field of an endoscope. The capsule-type endoscope is introduced from a mouth into a body cavity of the test subject. An imaging device in the capsule-type endoscope picks up images of alimentary canals such as the small intestine and the large intestine, whereby the capsule-type endoscope can collect information on the inside of the body cavity. An illumination unit (light emitting diode) and an objective lens are fixed in a front portion of the capsule-type endoscope, whereas a main block to which a circuit board is fixed and an outer casing which houses the main block are provided in a rear portion of the capsule-type endoscope. An image sensor, an electronic component that controls the image sensor, an electronic component for transmission, and a power switch, and the like are fixed to the circuit board, and an antenna board is connected to the circuit board. A battery is incorporated into the circuit board. The outer casing includes a hemispherical transparent cover and a cylindrical cover. A front portion of the main block is covered with the transparent cover, and a rear portion of the main block is covered with the cylindrical cover. A rear-end portion of the cylindrical cover is formed in a hemispherical shape. The circuit board is fixed to the main block, the main block is accommodated in the outer casing, and the capsule-type endoscope is assembled by bonding the transparent cover and the cylindrical cover in a watertight manner (for example, see JP-A (KOKAI) No. 2001-91860).